A study of dust airborne particles collected by vehicular traffic from the atmosphere of southern megalopolis Mexico City

Abstract

This study was made to assess airborne dust by sampling particles trapped in car air filters (CAFs) of Mexico City. The CAFs dust was analyzed by optical microscopy and SEM–EDX. The optical microscopy revealed that the dust contains organic matter; insect and plant debris and inorganic matter; quartz sand, plastics and polystyrene. This material was classified in different sizes (from 10 µm to 76 µm). Particulate matter (PM) trapped within the filter fiber arrangements were observed by SEM–EDX. PM of Mexico City was characterized as mainly agglomerated particles and fine particles. Agglomerates were mechanically disintegrated and main components were determined finding elements such as C, O, Si, Al, Ca and Fe. An impaction test was implemented to have insights into how agglomerates probably hit the filter surface, disintegrate and reintegrate other agglomerates. Pollen particles were frequently associated with agglomerated PM; its composition was analyzed, finding Pt on its surface among others. Likewise, the insect debris presented plenty of PM adhered to its surface. This work validates that CAFs are a simple, cheap and adequate sampling approach for further urban air quality evaluations.